Flash light lamp



n- 1934. J. A. M. VAN LIEMPT 1,944,854

FLASH mam" LAMP Filed Jan. 9, 1933 In0entor:

ZY/KWWM Patented Jan. 23, 1934 Johannes Antonius Maria. van

hoven, Netherlands, a Gloeilampenfabrieken;

Application January 9,

{ and in the Netherlands February 7 Claims.

'The present invention relates to flashlight lamps for photographicpurposes, and more particularly to means to increaseand improve theactinic effect of such flashlight lamps.

My invention may beapplied to various types of flashlight lamps,forinstance, to those in which the actinic effect is obtained by therapid com- ?bustion of a metal, for instance of aluminium foil providedin. an oxygen-containing sealed 1o bulb, or to flashlight lamp vpowderis provided in a sealed containe ignited by electric means.

Preferably my invention is applied to flashlight lamps of the typedescribedin the copending apluplication of 'van Liempt & Leydens, 'Ser.No.

594,910, ,filed February 24, 1932, in which the actinic effect isobtained primarily through a gas reaction which takesfplacdbetween thegases of a mixture, or through the decomposition of a single gas,enclosed in a sealed container,

and which reaction is preferably initiated by electrical ignition meansand more'particularly to a gas reaction flashlight lamp of the typedescribed in the copending application of Van Liempt and Leydens, Ser.No. 606,444 filed April Flashlight lamps of previous manufacture had thedrawback that due to the character of the light obtained the inherentcolor sensitiveness of orthochromatic and panchromatic photographicmaterial could not be always fully utilized.

In the above referred to two applications it has been suggested toprovide in the lamps certain substances, for instance, the salts ofcertain metals, to enhance the actinic effect, and to modify the colorspectrum of the light obtained by the reaction.

While it has been found that various salts and especially sodium salts,enhance to some extent the actinic effect of the light and improve itsspectrum, the results were not fully satisfactory, even on panchromaticand orthochromatic plates or films.

I have found that by providing sodium azide (NaNs) in the flashlightlamp, which decomposes easily and develops atomic sodium vapor, theactinic effect of the lamp is greatly improved, in correspondence withthe colour sensitiveness of the plate and the flashlight lamp obtains amuch higher intensity over a wide band around the well-known yellowsodium line. The fact that NaNs gives far better results than any othersodium compound is due to the fact that it easily produces a largeamount of Na vapour in atomic r and s in which a flashlight 'Liempt,Eindssignor to N. V; Philips Eindhoven, Netherlands 1933, Serial No.650,919",

state. Moreover in the case of the lamp described in the applicationSerial No. 606,444 not only the. intensity in the yellow range is in-.creased but also in the redrange, whereas the too high intensity of theblue is diminished. NaNa is 0 already decomposed by. a, temperature of350400 C. Y

While sodium azide generally improves the character of light and theactinic effect of flash light lamps of various types, the best resultsare 5 obtained when used in connection with flashlight lamps of the typedescribed in-said application Ser. No. 606,444, in which the actiniceffect is due to a reaction taking place ina gas mixture consisting ofcarbon disulphide and nitric oxide.

' -When sodium azide is added tosuch gas filling the atomic sodium vapordeveloped during the gas reaction, combined with the gas reaction,produces alight of exceedingly favorable properties,

in which high actinic effect, favorablespectrum distribution and quickreaction, are combined and which permits the full utilization of theinherent color-'sensitiveness of orthochromatic and panchromaticphotographic material, and also the taking of high quality instantaneousphotographs.

In the drawing accompanying this specification:

The figure is a schematic side view, partly in section, of a lampembodying my invention.

The bulb 1, which may be a standard incandescent lamp bulb, is providedwith a stem 2 and lead-in wires 3-3, which carry the. glower, which forexample, comprises two closely-spaced parallel wires 44 connected to theends of the leadin wires 3-3. Between the wires 44 is provided a film 6of sodium azide, which is deposited in a manner later to be explained.The lamp after being evacuated is filled with a gas mixture 5 of carbondisulphide and nitric oxide, for instance, one volume carbon dioxide to1.5 to 3.5 volumes of nitric oxide, or preferably 2.25 to 2.75 volumesof nitric oxide, such lamps and their manufacture 1 being more fullydescribed in said applications.

The sodium azide is introduced in the lamp by providing on the wires 44,preferably before the stem is sealed in the lamp, a preferably boilingaqueoussolution of'sgdium azide. The water is then evaporated whi'cl'fleaves the film 6 of sodium azide adhering between the two parallelwires.

The lamp is preferably providedwith a base '7 of the usual type to whichthe lead-in wires are connected, and. upon application of a suitablevoltage the gas mixture is ignited and simultaneously the sodium azideis decomposed to liberate atomic sodium vapor. The combined spectrumobtained by the reaction of the gas mixture and the spectrum of thesodium is such that a light having a photographic effect quite similarto day- 6 light or even better is obtained, and thus the color'sensitiveness of special photographic material fully utilized.

erence to a specific type of flashlight lamp, as

stated it can be applied to various types of fiashlight lamps. ThereforeI do not wish to be limitcd to the example shown, but desire theappended claims to be construed as broadly as permissible in view of theprior art.

What I claim is:

l. A flashlight lamp comprising a container,

electrical ignition means, and material which upon initiation by saidignition means enters into a reaction giving high actinic effect, andsodium azide on said ignition means to modify the actinic eifect of saidreaction.

2. A flashlight lamp comprising a sealed container, electrical ignitionmeans, and a gas filling in which a gas reaction may be brought about bysaid electrical ignition means, said gas reac tion giving a light of ahigh actinic effect, and sodium azide on said ignition means to modifythe actinic effect of said gas reaction.

3. A flashlight lamp for photographic purposes comprising a container,electrical ignition means, and material in which a gas reaction may bebrought about by said electrical ignition means, and sodium azide onsaid ignition means, which is decomposed and develops atomic sodiumvapor when said reaction takes place, said sodium vapor modifying theactinic effect of the lamp being essentially due to the gas reaction andto the sodium vapor.

4. A flashlight lamp for photographic purposes comprising a sealedcontainer, electrical ignition means, and a gas filling in which a gasreaction may be brought about by said electrical ignition means, andsodium azide on said ignition means to modify the actiniceffect of .thelamp, said electrical ignition not substantially contributing to theactinic effect of the lamp.

5. A flashlight lamp for photographic purposes comprising a container,electrical ignition means, and material which enters into a reactiongiving high actinic effect and adapted to being directly ignited by saidignition means, and sodium azide on said ignition means to modify theactinic effect of said reaction.

6. A flashlight lamp comprising a sealed container, electrical ignitionmeans, and a gas filling, said gas filling consisting of a mixture ofcarbon disulphide and nitric oxide, sodium azide provided on saidignition means, said lamp giving a high actinic effect upon ignition ofsaid gas filling, said actinic effect being modified by the lightemitted by atomic sodium obtained through the decomposition of saidsodium azide which takes place when the gas filling is ignited.

7. A flashlight lamp for photographic purposes comprising a transparentsealed container which is deprived of air and which contains a gasfilling, electrical ignition means in said lamp comprising an electricglower, said glower being provided with sodium azide, said gas. fillingadapted to be ignited by said electric ignition means to cause a. gasreaction having high actinic effect, said sodium azide adapted todecompose upon said ignition to liberate atomic sodium vapor whichmodifies the actinic effect of the lamp. J OHANNES ANTONTUS MARIA vanLIEMP'I.

